The use of vent panels for shielding electronic devices from electromagnetic interference (“EMI”) has been known for years. Typically, the vent panels utilize a filtering media being an electrically conductive (e.g., metallic) honeycomb structure, which is particularly effective in dissipating EMI from electronic equipment.
EMI shielding vent panels have found wide application in military equipment and high-performance electronic test equipment, where cost considerations are outweighed by performance requirements such as shielding effectiveness and ruggedness. One significant factor affecting costs is that the frames for such shielding vent panels are produced from welded aluminum extrusions. For a majority of commercial applications, the requirements for EMI shielding do not necessitate the use of these honeycomb vent panels.
However, the development of microprocessors with increasing clock frequencies for computer and telecommunication equipment now necessitates the use of honeycomb vent panels for EMI shielding. Unfortunately, current vent panel constructions do not facilitate the use of these honeycomb vent panels in commercial applications due to manufacturing costs associated with extruded aluminum frames.
One attempt to bypass the necessity of aluminum extruded frames is the use of stamped or die-cut sheet metal frames as disclosed in U.S. Pat. No. 6,426,459 to Mitchell. The disclosed frames are a one-piece structure with a series of spaced-apart tabs provided in at least one of the frame side walls to effect electrical contact with the honeycomb structured filtering media. While the disclosed frame obviates the need for aluminum extrusions, construction of the vent panel still requires significant metal working to effect electrical contact between the frame and the honeycomb filtering media.
In view of the above, there is a need in the art for vent panel constructions that facilitate their use in commercial applications. Accordingly, it is an object of the invention to provide EMI shielding vent panels with simpler and more efficient constructions.